Various methods are known for fusing toner particle images on substrates. In conventional fusing systems, one or both of a fuser roller and a pressure roller may be heated and are somewhat compliant to create a wide nip to allow sufficient heating area. Such conventional fusing systems typically provide gloss levels less than about 20 at a 20° measurement. Furthermore, the wide nip prevents obtaining sufficiently high pressure to remove the image relief in these materials.
Finishing color images containing fusible toner particles has been attempted in typical fusing systems. In these fusing systems, as noted above, typically the gloss is relatively low. As a result, systems for fusing colored images using methods and apparatus that result in fusing the black images to the substrate do not provide the desired gloss. Alternate methods have been used to produce enhanced gloss images by fusing the toner particle images and thereafter passing the substrate bearing the fused toner image to a cooling zone and then passing the cooled substrate bearing the fused toner image to a release zone where the cooled substrate bearing an enhanced gloss image is released.
Typically the cooling has been achieved by the use of a cooling device which has an air inlet with a plurality of downwardly directed small air inlets which are positioned above the fuser belt between the fuser roller and a release roller so that as the belt passes beneath the cooler with the substrates stuck to the bottom of the belt, the cooling air is blown downwardly onto the upper surface of the fuser belt to cool the belt. Coolers of this type have been widely used but are not efficient since the air blown downwardly toward the belt at most can travel one-half the width of the cooling device to the edge of the belt. As a result the cooling efficiency of the air is relatively low. Since it is desirable that a significant amount of cooling be achieved, improved methods and apparatus for achieving such cooling have been sought.